Dam.



G. BLAAUW.

DAM.

APPLICATION FILED MARA, 1913.

Patented Nov. 4, 1913.

3 SHEETS--SHBBT 1.

wir/VESSEL? ATTORNEYS COLUMBIA PLANOGRAPH Co..wAsNxNuToN, n. c.

G.- BLAAUW.

DAM.

APPLICATIQN FILED 111111. 1, 1913.

1,077,790. Patented N0v.4,1913.

3 SHEETS-SHBBT 2.

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G. BLAAUW.

DAM.

APPLIOATION FILED MAE.1,1913.

1,077,790, v Patented Nov. 4, 1913.

3 SHEETS-SHEET 3.

AHORA/EVS GEERT BLAAUW, F PITTSBURGH, PENNSYLVANIA.

DAM.

Specification of Letters Patent.

Patented Nov. e, 1913.

Application filed March 1, 1913. `Serial No. 751,442.

To all whom t may concern:

- Be it known that I, GEERT BLAAUW, ay citizen of the United States of YAmerica', and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made certain new and useful Improvements in Dams, of which the following is a specification.

My invention relates to dams of the kind provided with a number of hemispherical compartments spaced apart for the purpose of combining lightness and Voheapness with a maximum of strength and stability.

The objects of my invention may be summarized as follows I. To provide for holding, upon the top of the dam, a body of water of appreciable depth for the purpose of holding the dam down by the weight of the water. TI. To provide an improved pier construction in which allowance is made for free expansion and contraction of the entire top of the dam in the general direction vof the length thereof. IH. To construct a dam of concrete by aid of a hollow composite form builtup of units eX- actly alike, this form remaining permannently in the dam after being sealed therein by the addition of the concrete.

TV. To provide compartments of the daml with floors having the form of inverted domes, and thus to promote strength and stability without materially increasing the cost. lt may be stated in this connection that in the .construction of ordinary gravity dams, it is necessary to build them of massive size, and where uconcrete is employed, large volumes of the material are necessary in order to insure against the dam sliding. As concrete is very expensive, the amount of it used is of great importance, and where, as it is often the case, large quantities of it are employed for weighting` the dam ydown upon its foundation, the building of .the

structure is rendered unduly expensive.

p It may be remarked that sufficient provision is not ordinarily made in the construction of dams to allow for the free eX- pansion and contraction of the entire dam, in the general direction of its length. I provide against this evil as hereinafter described. It may further be observed that in ordinary concrete constructions, it is necessary to employ wooden forms, and to remove them during the building operation after the concrete has had time to set. This entails further expense, which I remedy by the use of my improved unit blocks, which, when put together, and the concrete added, form therewith a part of the dam; and by the shape in which I build them they materially increase the strength of the dam. Besides these advantages, l build my dam so as to distribute the pressures due to the water and weight of the dam to good advantage, and I also seek to prevent the possibility of uplifting the dam by water pressure exerted against the underside thereof. These and other advantages are promoted by use of the structure herein shown and described.

Reference is made to the accompanying drawings forming a part of this specification, and in which like letters indicate like parts.

Fig. 1 is a cross section through the damy and is taken uponthe line 1?-1 of Fig. Il, looking in the direction of the arrows. Fig. 2 is a fragmentary view corresponding to the lower portion of Fig. 1, but showing the floor as omitted, the bottom of the hemispherical compartment being thus bounded by native rock. F ig. 3 is an elevation of the dam complete showing it as seen byl an observer standing at the right of Fig. l, and looking up stream. Fig. t is a plan view of the dam, the upper portion of the figure corresponding to up stream and the lower portion of the figure corresponding to down stream. Fig. 5 is a detail showing in perspective, one of the unit blocks.' Fig. 6 is a detail showing in fragmentary longitudinal section, one of the steel ties employed Fig. 7 is a cross section through one of the steel ties.

The wall of the dam is shown atV 8 and is built of concrete, and is provided with large hemispherioal compartments 8a. The dam is further provided with a floor 9, made in this instance of concrete, and which rests upon a foundation 10, preferably of native rock. The floor 9 is provided with weep holes l1 for preventing water pressure from accumulating under the dam and uplifting the same. Within each compartment 8El and forming a, portion of the wall of the dam are unit blocks 12, each having substantially the form of a keystone, as indieated in Fig. 5. These blocks may be made of earthenware or of any other suitable material. They are first built into the form of a dome, after which the concrete is poured upon them and properly formed upon the outside. When the concrete sets, it holds the units firmly in position so that they cannot be removed exceptby destroying the dam. Each compartment is provided with an outlet 13 to facilitate the escape of such water as may ind its way into the compartment. U

lntegral with the wall 8a of the dam are the piers 1% which are arranged in pairs, as shown, the piers of each pair being connected together by ties 15. These ties may be of any desired form and made of any suitable material, but l ind it convenient to make them of latticed steel work, as indicated more particularly in Figs. 6 and 7, beams 17 of metal, preferably steel, being connected by links 1S secured to them and forming with them a type of lattice work.

The foregoing description applies to one section oi the dam, which in its entirety comprises a number of such sections arranged as indicated in Fig. t and separated by expansion joints 14?; that is to say, the pier 14 of one section practically abuts against the adjacent pier 14 of the next .successive section, there being just sufficient clearance to allow for expansion and contraction of the sections, this amount of clearance being negligible for other purposes.

A gate 16 is mounted in each section which for this purpose is provided with ways 19. Any type of gatemay be used for this purpose. The water above the dam that is to say, the water located up stream from the gates-is shown at 20, and at 21 a portion of this water, of appreciable depth, extends out over and rests directly upon the top of the dam. The water below the dam is shown at 22.

In some instances, as where economy of construction is of greater importance than strength, I omit the floor 9 and. rest the concrete. and the unit blocks directly upon a rock foundation 10a, as indicated in Fig. 2.

The operation of my device is'as follows :#The gates being closed, the water above the dam is allowed to accumulate until its depth above the dam is commensurate with the height of the gates, or is as great as may be allowed by the environment of the mechanism. TheY greater the depth of water 21 above the dam, the greater becomes the weight or downward pressure of the water, and this increases the stability of the dam. That is to say, when the water is deepest', and its pressure is the greatest, thus tending to break through the dam, the weight of the portion of water 21 becomes most effective in holding the dam down. The floor 9 because of its inverted dome shape possesses great strength in that it embodies the principle of the inverted arch.

l do not limit myself to the precise construction shown, as variations may be made therein without departing from the spirit of my invention, the scope of which is com- `mensurate with my claims.

1. A dam comprising a wall having a series of substantially hemispherical com partments spaced apart on the underside thereof, and means for corralling a body of water of appreciable depth upon said darn for the purpose of weighting the same down.

2. A dam made in sections, each section being provided at its ends with piers, and tie members extending lengthwise of each section for the purpose of enabling the piers of each section to act together, said sections being separated by, expansion joints to allow for expansion and contraction throughout the entire dam in the general direction of the length thereof.

3. A hollow dam comprising a wall having a plurality of pockets, each pocket having a floor in the form of an inverted dome.

4. A hollow dam comprising a substantially hemispherical dome made of unit blocks loose relatively to each other, said dome being surrounded by concrete and provided with a floor, the upper surface of said floor being concave.

Y GEERT BLAAUW. `Witnessesz ROY E. WARD, E. C. ALFoRD.

Copies of th'is patent may be obtained for vveeents each, by addressing the Commissioner of Patents, Washington, D. Q. Y A l 

